Multipiece cutting edge attachment for spring tines of a harrow

ABSTRACT

A multi-piece cutting edge attachment for a circular shaft of a harrow tine features a mounting member formed of a material that is weldable to, and distinct from, a first material of the harrow tine. A cutting edge member is formed of a third material that is harder than the first and second materials and less weldable to harrow tine than the second material of the mounting member. The cutting edge member has a front face and an opposing rear face that is conformingly shaped for placement against a front face of the mounting member at a lower end thereof. The multi-piece arrangement forms a cutting edge of greater hardness than that which is achievable by a material directly attachable to the tine itself.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. 119(e) of U.S.Provisional Patent Application Ser. No. 61/702,888, filed Sep. 19, 2012.

FIELD OF THE INVENTION

The present invention relates generally to harrow tines, and moreparticularly to a two-piece attachment for defining a hardened cuttingedge at the lower end of the tine shaft by using a mounting piece of afirst material suitable for easy and secure attachment to the tine and acutting edge piece of a harder second material for maximum durabilityand wear life.

BACKGROUND OF THE INVENTION

A spring harrow is an implement featuring a frame that is towed over theground by an agricultural tractor so that a set of spring tinesdepending downward from the frame engage the ground surface to break upand smooth out the same. A common type of spring harrow employs a doublecoil spring tine, where a pair of horizontally spaced apart coils windaround a shared horizontal axis with inner ends of the coils joinedtogether by a central cross-bar running parallel to that axis. A pair oftine shafts depend downwardly from the outer ends of the two coils. Thecentral cross-bar is mounted to the implement frame and the coilsindependently and respectively bias the two tine shafts downward aboutthe coil axis to keep the lower ends of the tine shafts engaged with theground. Single coil tines are sometimes also used, where each tinefeatures only a single coil spring and single respective downward tineshaft.

A known problem with spring tines is they may tend to wear relativelyquickly, and accordingly require frequent replacement.

U.S. Pat. No. 6,425,446 of Gates addresses this issue by mounting aone-piece hardened edge member to a front side of each tine shaft at thelower end thereof to increase the effective hardness at the leading sideof the lower portion of the resulting tine structure. The member is madeof chrome to provide greater hardness than the spring tine material,while being suitable for attachment to the spring tine by welding.

While the Gates solution does provide a cutting edge of improveddurability relative to the tine itself, there remains room forimprovement, as use of more durable materials than chrome, such astungsten carbide, would further improve the wear life of the tine, butchallenges remain in how to attach a tungsten carbide wear piece to thetine, as the tungsten carbide is not suitable for welded attachment tothe spring tine.

Applicant has addressed this problem through development of a uniquetwo-piece cutting edge attachment for harrow tines.

Other references relating to attachments for mounting on spring tinesinclude U.S. Pat. Nos. 184,089, 4,834,190, 5,027,907 and 6,138,771, andJapanese Patent Document 11172646, which individually and collectivelyfail to suggest the solution put forth by the present invention.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a cuttingedge attachment for a circular shaft of a harrow tine formed of a firstmaterial, the attachment comprising:

a mounting member formed of a second material that is weldable to thefirst material of the harrow tine, the mounting member having a rearportion shaped for attachment to the circular shaft of the harrow tineadjacent a lower end thereof to position a front face of the mountingmember in front of a front surface of the circular shaft;

a cutting edge member of a third material that is harder than the firstand second materials and less weldable to the first material of theharrow tine than the second material of the mounting member, the cuttingedge member having a front face and an opposing rear face that isconformingly shaped for placement against the front face of the mountingmember at a lower end thereof;

whereby the cutting edge member is mountable on the front face of themounting member which is in turn weldable to the circular shaft of theharrow tine to carry the cutting edge member in front of the lower endof the circular shaft of the harrow tine, where the front face of thecutting edge member forms a cutting edge of greater hardness than theharrow tine.

Moving forwardly away from the rear side, the mounting member flaresoutwardly to a wider area of said mounting member having a width thatexceeds said rear side of the mounting member and equals or exceeds afull-diameter of the circular shaft.

According to a second aspect of the invention there is provided a harrowtine with a cutting edge, the harrow tine comprising:

a circular shaft formed of a first material and having a front surfaceand an opposing rear surface;

a mounting member comprising a second material distinct from the firstmaterial, the mounting member being attached to the circular shaftadjacent a lower end thereof in a position placing a front face of themounting member forwardly of the front surface of the circular shaft;and

a cutting edge member comprising a third material distinct from andharder than each of the first and second materials, the cutting edgemember being attached to the front face of the mounting member to carrythe cutting edge member in front of the lower end of the circular shaftof the harrow tine, where a front face of the cutting edge member formsa hardened cutting edge of greater hardness than the circular shaft.

The rear side of the mounting member spans less than a full-diameter ofthe circular shaft of the harrow tine at an interface between said frontsurface of the circular shaft and said rear side of the mounting member,and moving forwardly away from the rear side, the mounting member flaresoutwardly to an area having a width that exceeds said interface andequals or exceeds said full-diameter of the circular shaft.

Preferably the front face of the mounting member comprises a taperedupper portion that narrows forwardly to a pointed edge, and a flattenedlower portion for seating of the rear face of the cutting edge memberthereagainst.

The flat surface of the front face of the mounting member may berecessed rearwardly from an entirety of the pointed edge of the upperportion of the front face of the mounting member.

The front face of the cutting edge member may be tapered to narrow in adirection moving away from the rear face to a sharpened front edge, inwhich instance the tapered upper portion of the front face of themounting member and the front face of the cutting edge member may betapered at a matching angle.

In embodiments where the cutting edge member is tapered and a flatsurface of the mounting member is recessed from a tapered upper portion,a thickness of the cutting edge member measured from the rear facethereof to the sharpened front edge may equal a thickness of themounting member measured from the flattened lower portion of the frontface of the mounting member to the pointed edge of the upper portion ofthe mounting member.

In other embodiments, the front face of the cutting edge member may beflat. In such instance, a thickness of the cutting edge member measuredbetween the front and rear faces thereof may be less than a thickness ofthe mounting member measured from the flat surface of the front face ofthe mounting member to the pointed edge of the upper portion of themounting member.

Preferably the mounting member comprises chromium carbide.

Preferably the cutting edge member comprises tungsten carbide.

The cutting edge member may comprise multiple pieces for placement ondifferent respective portions of the front face.

Preferably, at an upper area approaching a top end of the mountingmember, the mounting member narrows toward said top end of the mountingmember in at least one of a thickness dimension and a width dimension.

Preferably the mounting member comprises a tapered region that decreasesin thickness moving away from the lower end of the mounting member.

According to a third aspect of the invention there is provided a methodof providing a cutting edge on a circular shaft of a harrow tine made ofa first material, the method comprising:

(a) with a mounting member comprising a second material distinct fromthe first material, attaching said mounting member to the circular shaftadjacent a lower end thereof in a position placing a front face of themounting member forwardly of the front surface of the circular shaft;and

(b) before or after step (a), with a cutting edge member that comprisesa third material distinct from and harder than each of the first andsecond materials, attaching said cutting edge member to the mountingmember in a position over the front face thereof;

whereby a front face of the cutting edge member defines a hardenedcutting edge carried ahead of the circular shaft of the harrow tine on aside of the mounting member opposite said shaft.

Preferably step (a) comprises welding the mounting member to thecircular shaft of the harrow tine.

Preferably step (b) comprises attaching the cutting edge member to themounting member by way of a non-welding attachment technique.

Preferably step (b) comprises brazing the cutting edge member to themounting member.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, which illustrate exemplary embodiments ofthe present invention:

FIG. 1 is a perspective view of a double coil spring harrow tinefeaturing a two piece cutting edge attachment of a first embodiment ofthe present invention on each downwardly extending shaft of the tine.

FIG. 2 is a close up side view of the cutting edge attachment on one ofthe shafts of the tine of FIG. 1.

FIG. 3 is a close up perspective end view of the cutting edge attachmentof FIG. 2.

FIG. 4 is a close up side/front perspective view of a cutting edgeattachment of a second embodiment of the present invention.

FIG. 5 is a close up perspective end view of the cutting edge attachmentof FIG. 4.

FIG. 6 is a perspective view of a cutting edge attachment of a thirdembodiment of the present invention.

FIG. 7 is a front view of the cutting edge attachment of FIG. 6.

FIG. 8 is a side view of the cutting edge attachment of FIG. 6.

FIG. 9 is an end view of the cutting edge attachment of FIG. 6 from anupper end thereof.

FIG. 10 is an end view of the cutting edge attachment of FIG. 6 from alower end thereof.

FIG. 11 is a cross-sectional view of the cutting edge attachment of FIG.8 as taken along line XI-XI thereof.

DETAILED DESCRIPTION

FIG. 1 illustrates application of the present invention to aconventional double coil spring tine 10 consisting of two shafts 12depending downward from the outer ends of a pair of coaxial coils 14that are horizontally spaced apart from one another along their sharedhorizontal axis by a central cross-bar 16. The present invention adds acutting edge attachment 20 to the lower end of each tine shaft 12 toincrease the hardness of the structure on the leading side of the shaftthat engages in the ground during use of the tine.

More particularly, the illustrated embodiments employ a two-pieceattachment structure in which a base or mounting member 22 is made of afirst material suitable for welded attachment to the tine shaft, and aworking or cutting edge member 24, 24′ of a second harder material iscarried at an exposed position at the front side of the mounting member22 to provide improved durability at the bottom end of the tine shaft.This provides the benefit of allowing use of a highly durable materiallike tungsten carbide to form the cutting edge of the tine, whileallowing welded installation of the attachment despite the tungstencarbide's unsuitability for welded attachment to the spring steel of thetine.

Forming the mounting member 22 of a weld-friendly material such aschrome carbide, which has a hardness greater than that of the springsteel but less than that of the tungsten carbide, thus allows easyinstallation of the attachments with conventional welding techniques forsecure, relatively permanent fastening to the tine, while the attachmentof the cutting edge piece to the mounting member, for example bybrazing, further improves the durability of the at the bottom end of thetine shaft compared to use of the chrome carbide piece alone.

Mounting members 22 of the same shape are used in the two illustratedembodiments. With reference to FIG. 5, a backside 25 of the mountingmember is arcuately curved in a concave manner to conform with theconvex peripheral surface of the circular-section tine shaft 12 on thefront side of the shaft that leads the opposing rear side when the tineis conveyed along the ground by a harrow or other implement on which thetine is mounted. The mounting member 22 is linear in its length, whichruns parallel to the longitudinal axis of the linear shaft 12 of thetine. The arcuate curve in the backside of the mounting member lies incross-sectional planes perpendicular to its length, and is uniform overthe full length of the mounting member. The concave backside of themounting member spans less than 180-degrees so that the mounting memberdoesn't fully span the diameter of the tine shaft at its conforminginterface against the front side of the shaft.

With continued reference to FIG. 5, moving forwardly away from itsconcave backside placed against the tine shaft, the mounting member 22has rear side walls 26 that flare laterally outward to increase thewidth of the mounting member relative to its point of contact with theshaft. These rear side walls 26 are both flat and are symmetric to oneanother across a central longitudinal plane that contains thelongitudinal axis of the tine shaft and cuts radially through the apexof the concave backside of the mounting member. Front side walls 28 arelikewise flat and symmetric about the central longitudinal plane, andconverge forwardly from the rear side walls 26, providing a forwardlytapered shape that narrows forwardly from the widest point of themounting member. At the widest point of the mounting member, i.e. in theplane containing the two parallel edges at which the front and rear sidewalls meet on the opposite sides of the mounting member, the mountingmember preferably has a width equal to or slightly exceeding thediameter of the tine shaft, thus presenting a full width shield over theforward facing half of the shaft circumference for optimum protectionthereof by the harder mounting member.

At a lower portion 30 of the mounting member 22 the front side walls 28are truncated by a plane that is parallel to the length of the mountingmember and parallel to the tangent of the apex of the concave backsideof the member, thus forming a flat front face 32 over the height of thislower portion of the mounting member 22. Above this flattened lowerportion 30 of the mounting member 22, the front side walls 28 are nottruncated, and instead intersect with another to form a forwardlypointing peak that runs in the lengthwise direction of the mountingmember to define a linear edge 34 at an upper portion 36 of the mountingmember. The sharpened peak at the front of the upper portion of themounting member is believed to better break up straw during use of theimplement, and thereby help the straw clear the tine as the implementmoves forward.

At the upper portion 36 of the mounting member 22, the intersectingfront side walls 28 thus form two sides of a right-angle triangularprism that runs upward from the flattened lower portion 30 of themounting member to the top end of the pointed linear edge 34, and whoseimaginary third side is formed by the plane defined by the maximum widthof the cutting member (i.e. the plane containing the parallel edges atwhich the front and rear side walls intersect at both sides of thecutting member). At the top of the mounting member 22, the triangularprism shape projecting forward from the maximum width of the cuttingmember is truncated at an oblique plane so as to form a triangular upperface 38 that slopes downwardly and forwardly from the top end of themember 22.

The mounting member 22 is welded to the tine shaft, for example asillustrated in the drawings by beads of welding material 40, 42 runningdownward along the shaft at the rear side walls 26 of the mountingmember 22 and across the bottom end of the mounting member. Theobliquely sloped upper end of the mounting member reduces theopportunity for straw to build up at the transition between the mountingmember and the tine shaft during use of the implement.

In the first embodiment of FIGS. 1 to 3, the cutting edge member 24 isprovided in the form of a flat, rectangular, bar-shaped piece oftungsten carbide having uniform thickness. The flat piece 24 has alength spanning that of the flattened lower portion 30 of the mountingmember, thus extending from the bottom end of the mounting member 22 upto the triangular face 44 at the right angle transition between thepeaked upper portion 36 of the mounting member 22 and the flattenedlower portion 30 recessed back from the peak 34 of the upper portion.The width of bar likewise spans the full width of the flattened frontface 32 of the lower portion of the mounting member 22. The rectangularrear face of the flat piece 24 sits flush against the flattened frontface 32 of the mounting member's lower portion. The thickness of theflat piece 24, measured from its flat rear face to its opposing fiatrectangular front face 46, is the smallest of the piece's threedimensions, and is less than the distance by which the peaked upperportion of the mounting member 22 projects from the flat front face ofthe flattened lower portion of the mounting member 22. The flat frontface of the bar 24 is thus recessed back from the linear edge 34 at theleading peak or point of the upper portion of the mounting member 22.The reduced thickness may contribute to prevention of straw buildup onthe corners of the cutting edge member compared to use of a thickerrectangular piece.

Having the flattened front face of the mounting member 22 in a planecutting through the front side walls, rather than positioned furtherback at or behind the widest point of the mounting member, acts to keepa notable distance between the rear side wall areas at which themounting member is welded to the tine shaft and the flattened front areaat which the cutting edge member 24 is brazed to the mounting member 22.This way, when the mounting member is welded onto the tine shaftsometime after the cutting edge member is brazed to the mounting member,the heat from the weld does not weaken the brazed joint. Accordingly,the cutting edge member can be brazed to the mounting member by themanufacturer, and the resulting prefabricated attachment assembly canthen be installed by a single process of welding to the tine shaft by aninstaller (e.g. the implement owner) at the site where the implement isnormally used, stored or serviced.

The second embodiment of FIGS. 4 and 5 differs from the first embodimentonly in the shape of the cutting edge member 24′, which instead of athin, bar-like rectangular prism, has the shape of an obliquelytruncated triangular prism. In the second embodiment, the cutting edgemember thus has a form more similar to the upper portion of the mountingmember than the flat bar cutting edge member 24 of the first embodiment.

The triangular cutting member 24′ has a flat rear face that sits flushagainst the flat front face of the lower portion of the mounting member22, and two sides walls 48 that converge together forwardly from theflat rear face of the member 24′ to intersect at a linear peak 50. Theupper end of the cutting edge member 24′ is a triangular surface lyingat a right angle to the flat rear face of the cutting edge member 24′ soas to abut flush against the matching triangular surface 44 at the lowerend of the mounting member's upper portion. The lower end of the cuttingedge member 24′ is where the piece deviates from its otherwiseright-angle prism shape, as the lower end is truncated by an obliqueplane to define a triangular lower end surface 52 sloping upwardly andforwardly from the lower end of the mounting member 22 to the peak 50 ofthe cutting edge member 24′. The oblique angle of the bottom end of thecarbide is to add strength as compared as to if the lower end of thecarbide was at a 90-degree angle, which could create a sharper point atthe lower end of the linear peak 50.

The thickness of the triangular cutting edge member, i.e. theperpendicular distance from its flat rear face to its forward peak,matches the perpendicular distance by which the upper portion of themounting member projects forwardly from the flat front face of the lowerportion. The flat rear face of the triangular cutting edge member 24′has a width matching that of the flat front face of the lower portion ofthe mounting member 22, and the angle at which the side walls 48 of thecutting edge member 24′ converge matches the angle of convergence of thefront side walls 28 of the mounting member. Accordingly, the linear edgeformed by the peak 50 of the cutting edge member 24′ forms a continuous,in-line extension of the linear peak edge 34 of the upper portion of themounting member 22, and the side walls 48 of the cutting edge member 24′each form a continuous, coplanar extension of the respective front sidewall 28 of the mounting member 22.

In each embodiment, the forwardly narrowing shape of the tapered upperportion of the mounting member forms a sharpened leading edge of themounting member at a height spaced a distance upward from the lower endof the tine shaft. In the second embodiment, the cutting member likewisetapers forwardly in order to narrow to a sharpened cutting edge alignedwith the sharpened leading edge of the mounting member. In the firstembodiment, the flat front face of the cutting edge member instead formsa wider, flat cutting edge set back from the sharpened leading edge ofthe mounting member. In each case, the lower portion of the mountingbody carries a distinct, separately formed body of tungsten carbide toprovide optimum durability and wear resistance at a location rising ashort distance upward from the bottom end of the tine shaft, where themost ground contact will occur during use of the tine. The exposed upperportion of the mounting body, though not as strong as the cutting edgebody, still provides increased wear resistance over a slightly higherportion of the tine shaft where some contact with the earth is stillexpected, compared to use of a tine without any hardened cutting edgeattachment. Having the mounting body run the full length of the cuttingedge body in front of it ensures a strong, secure connection of thecutting edge body to the tine.

FIGS. 6 to 10 illustrate a third embodiment of similar form to the firstembodiment, but with some notable changes including replacement of thesingle bar-shaped piece of tungsten carbide with two shorter flatrectangular bar-shaped pieces 24 a, 24 b abutted end to end to form thecutting edge member 24″, and use of a tapered shape at both the upperand lower portions of the mounting member 22′ that increases thethickness of each portion when moving downward along the lengthwisedimension of the mounting member. The upper portion thus not only growsnarrower moving in the forward direction when mounted on the tine inorder produce a forwardly pointing peak 34′, but also grows thinner(i.e. smaller in the fore/aft direction) moving upwardly along the tine,as does the lower portion. The upper portion also tapers in width at anupper region thereof toward the top end of the mounting member.

Each piece 24 a, 24 b of the two-piece cutting edge arrangement of thethird embodiment occupies a respective half of the overall length of themounting member's lower portion, and each substantially spans the fullwidth of the flattened front face of the lower portion of the mountingmember. The use of a plural number of smaller carbide pieces eachspanning a different respective partial portion of the flattened frontface of the mounting member reduces the risk of breakage of the carbidein the heating and cooling cycle it experiences during welding of themounting member to the tine.

The tapered thickness of the mounting member 22′ of the third embodimentis best shown in FIG. 8. Turning briefly to FIG. 10, as in the otherembodiments, the plane of the flattened front face 32′ of the mountingmember is perpendicular to a radial plane P that contains the apex 60 ofthe uniform-radius arcuate rear side of the mounting member and the axisA from which the radius R of the arcuate rear side is measured. However,unlike the other embodiments, the plane of the flattened front face 32′of the lower portion of the mounting member 22′ is not parallel to axisA (which is generally coincident with the longitudinal axis of the tineshaft when the mounting member is installed thereon). Instead, referringto FIG. 8, the plane of the flattened front face 32′ is obliquely slopedrelative to this axis A at a small angle so that the lower portion ofthe mounting member of the grows thicker moving in a downward directionalong the length of the mounting member. This thickness dimension may bemeasured as the distance between the flattened front face 32′ and theapex 60 of the mounting member's concave backside. In other words, theplane of the front face 32′ is tilted out of parallel alignment with atangential plane T at the apex 60 of the concave rear side of themounting member.

Similarly, the peak edge 34′ of the upper portion 36′ of the mountingmember is obliquely sloped at a small angle relative to axis A andtangential plane T so that the upper portion of the mounting member alsoincreases in thickness (for example, as measured between the apex 60 ofits arcuately concave rear side and its leading peak 34′) as you move inthe downward direction along the axis A. In the illustrated embodiment,the peak edge 34′ of the upper portion and the flattened front face 32′of the lower portion are parallel, i.e. sloped at the same anglerelative to the axis A or tangential plane T.

When the mounting member is installed on a tine, it thus projectsfurther forwardly from the tine at the lower end of the peak 34′ thanover the remainder of the upper portion, and projects further forwardlyfrom the tine at the lower end of the lower portion than over theremainder of the lower portion. In the illustrated embodiment, thebottom edge of the flattened front face 32′ of the lower carbide piece24 b is generally the same radial distance from axis A as the lower endof the upper portion's peak 34′ so that the carbide pieces 24 a, 24 b ofthe cutting edge portion 24″ project no further forward from the tinethan the peak 34′ of the mounting portion. That is, the combinedthickness of the lower carbide piece 24 b and the mounting member at thelower end thereof is generally equal to, and does not exceed thethickness of the mounting member at the lower end of the upper portionthereof.

As a result of this tapered configuration of the upper and lowerportions of the mounting member, there is a less dramatic transitionfrom the straight metal tine shaft or bar to the top of the mountingmember when installed, while a significant material thickness at thebottom end of the mounting member remains intact in order to provideadequate support and room for welding of the mounting member to thetine.

In order to maintain a uniform width over the full length of theflattened front face 32′ of the lower portion of the mounting member toallow for a uniform width of the cutting edge member to be mountedthereon, while still retaining a uniform overall width of the mountingmember over the lower portion and over the peaked lower part of theupper portion, an angle of slope by which each side of the mountingmember intersects the plane of the flattened front face 32′ of themounting member 22′ varies as you move along the lengthwise direction ofthe lower portion of the mounting member. That is, the side of themounting member slopes more dramatically inward toward the lateralcenter of the mounting member at the top end of the flattened front face32′ than at the lower end so that the resulting width of the flattenedfront face is the same at both the thinner top end of the mountingmember's lower portion and the thickener bottom end of the mountingmember's lower portion.

This is best illustrated by reference to FIGS. 10 and 11, where theacute angle measured between the plane of the flattened front face 32′and the plane of side wall joined thereto on each side of the mountingmember is labelled Θ at the lower end of the mounting member (FIG. 10),and is labelled φ in a cross-sectional plane near the upper end of thelower portion (FIG. 11), and φ is less than Θ. The cross-section of themounting member is symmetric about plane P, and so although the sidewall to front face angle is marked only one side of the mounting memberin each of these figures, the other side is a mirror image, and thusfeatures the same angular configuration between the respective side walland the flattened front face. The angle of each of these side walls ofthe mounting member varies smoothly over the lengthwise direction fromone end of the lower portion to the other.

To further increase the smoothness of the transition between the upperend of the mounting member and the tine shaft, the upper portion of themounting member of the third embodiment is not only tapered in thicknessby the slope of the plane of the upper face 38′, but additionally tapersin width, as best seen at 62 in FIG. 7 by convergence of the side wallstoward one another in a manner symmetric about the plane P from near theprism-shaped lower part of the upper portion to the very top end of theupper portion.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of same madewithin the spirit and scope of the claims without department from suchspirit and scope, it is intended that all matter contained in theaccompanying specification shall be interpreted as illustrative only andnot in a limiting sense.

The invention claimed is:
 1. A cutting edge attachment for a circularshaft of a harrow tine formed of a first material, the attachmentcomprising: a prefabricated mounting member comprising a solid bodyhaving a predefined shape and formed of a second material that isweldable to the first material of the harrow tine, the solid body havinga front face and an opposing rear side, the front face of the mountingmember having a flat surface at a lower end thereof and the rear sidehaving a concavely arcuate curvature for conforming attachment to afront surface of the circular shaft of the harrow tine adjacent a lowerend thereof to position the front face of the mounting member in frontof the front surface of the circular shaft; a cutting edge member ofgeometric shape and comprising a third material that is harder than thefirst and second materials and less weldable to the first material ofthe harrow tine than the second material of the mounting member, thecutting edge member having a front face and an opposing flat rear facefor flush placement against the flat surface of the front face of themounting member at a lower end thereof with a remainder of the cuttingedge member residing in an exposed position in front of theprefabricated mounting member; whereby the cutting edge member ismountable on the front face of the mounting member, which is in turnweldable to the circular shaft of the harrow tine to carry the cuttingedge member in front of the lower end of the circular shaft of theharrow tine, where the front face of the cutting edge member forms acutting edge of greater hardness than the harrow tine; wherein movingforwardly away from the rear side, the mounting member flares outwardlyto a wider area of said mounting member having a width that exceeds saidrear side of the mounting member and equals or exceeds a full-diameterof the circular shaft.
 2. The cutting edge attachment of claim 1 whereinthe front face of the mounting member, at an upper area thereof abovethe flat surface, comprises a tapered upper portion that narrowsforwardly to a pointed edge.
 3. The cutting edge attachment of claim 2wherein the flat surface of the front face of the mounting member isrecessed rearwardly in a horizontal direction from an entirety of thepointed edge of the upper portion of the front face of the mountingmember.
 4. The cutting edge attachment of claim 3 wherein the front faceof the cutting edge member is tapered to narrow in a direction movingaway from the rear face to a sharpened front edge.
 5. The cutting edgeattachment of claim 4 wherein the tapered upper portion of the frontface of the mounting member and the front face of the cutting edgemember are tapered at a matching angle.
 6. The cutting edge attachmentof claim 5 wherein a thickness of the cutting edge member measured fromthe rear face thereof to the sharpened front edge equals a thickness ofthe mounting member measured from the flat surface of the front face ofthe mounting member to the pointed edge of the upper portion of themounting member.
 7. The cutting edge attachment of claim 1 wherein thefront face of the cutting edge member is tapered to narrow in adirection moving away from the rear face to a sharpened front edge. 8.The cutting edge attachment of claim 1 wherein the front face of thecutting edge member is flat.
 9. The cutting edge attachment of claim 2wherein the front face of the cutting edge member is flat.
 10. Thecutting edge attachment of claim 3 wherein the front face of the cuttingedge member is flat, and a thickness of the cutting edge member measuredbetween the front and rear faces thereof is uniform and less than athickness of the mounting member measured from the flat surface of thefront face of the mounting member to the pointed edge of the upperportion of the mounting member.
 11. The cutting edge attachment of claim1 wherein the mounting member comprises chromium carbide.
 12. Thecutting edge attachment of claim 1 wherein the cutting edge membercomprises tungsten carbide.
 13. The cutting edge attachment of claim 1wherein the cutting edge member comprises multiple pieces for placementon different respective portions of the front face of the mountingmember.
 14. The cutting edge attachment of claim 1 wherein, at an upperarea approaching a top end of the mounting member, the mounting membernarrows toward said top end of the mounting member in at least one of athickness dimension and a width dimension.
 15. The cutting edgeattachment of claim 1 wherein the mounting member comprises a taperedregion that decreases in thickness moving away from the lower end of themounting member.
 16. A harrow tine with a cutting edge, the harrow tinecomprising: a circular shaft formed of a first material and having afront surface and an opposing rear surface; a prefabricated mountingmember attached to the circular shaft and comprising a solid body of asecond material that is distinct from the first material, the solid bodyhaving a predefined shape comprising a front face and an opposing rearside, the front of the mounting member having a flat surface at a lowerend thereof and the rear side having a concavely arcuate curvatureresiding in conforming abutment with a front surface of the circularshaft adjacent a lower end thereof in a position placing the front faceof the mounting member forwardly of the front surface of the circularshaft; and a cutting edge member of geometric shape attached to the flatsurface of the front face of the mounting member and comprising a thirdmaterial distinct from and harder than each of the first and secondmaterials, the cutting edge member having a front face and an opposingflat rear face that resides in flush abutment against the flat surfaceof the front face of the mounting member with a remainder of the cuttingedge member residing in an exposed position in front of theprefabricated mounting member so that the front face of the cutting edgemember forms a hardened cutting edge of greater hardness than thecircular shaft at a position forward thereof; wherein the rear side ofthe mounting member spans less than a full-diameter of the circularshaft of the harrow tine at an interface between said front surface ofthe circular shaft and said rear side of the mounting member, and movingforwardly away from the rear side, the mounting member flares outwardlyto an area having a width that exceeds said interface and equals orexceeds said full-diameter of the circular shaft.
 17. The cutting edgeattachment of claim 1 wherein the mounting member comprises chromiumcarbide, the cutting edge member comprises tungsten carbide and thecutting edge member is brazed to the mounting member.
 18. The cuttingedge attachment of claim 16 wherein the mounting member compriseschromium carbide, the cutting edge member comprises tungsten carbide andthe cutting edge member is brazed to the mounting member.